chore(all): review error wrappings

- remove repetitive `cannot` and `failed` prefixes
- rename `unmarshaling` to `decoding`

internal/vpn/openvpn.go

@@ -18,19 +18,19 @@ func setupOpenVPN(ctx context.Context, fw Firewall,
 	logger openvpn.Logger) (runner *openvpn.Runner, serverName string, err error) {
 	connection, err := providerConf.GetConnection(settings.Provider.ServerSelection, ipv6Supported)
 	if err != nil {
-		return nil, "", fmt.Errorf("failed finding a valid server connection: %w", err)
+		return nil, "", fmt.Errorf("finding a valid server connection: %w", err)
 	}
 
 	lines := providerConf.OpenVPNConfig(connection, settings.OpenVPN, ipv6Supported)
 
 	if err := openvpnConf.WriteConfig(lines); err != nil {
-		return nil, "", fmt.Errorf("failed writing configuration to file: %w", err)
+		return nil, "", fmt.Errorf("writing configuration to file: %w", err)
 	}
 
 	if *settings.OpenVPN.User != "" {
 		err := openvpnConf.WriteAuthFile(*settings.OpenVPN.User, *settings.OpenVPN.Password)
 		if err != nil {
-			return nil, "", fmt.Errorf("failed writing auth to file: %w", err)
+			return nil, "", fmt.Errorf("writing auth to file: %w", err)
 		}
 	}
 
@@ -42,7 +42,7 @@ func setupOpenVPN(ctx context.Context, fw Firewall,
 	}
 
 	if err := fw.SetVPNConnection(ctx, connection, settings.OpenVPN.Interface); err != nil {
-		return nil, "", fmt.Errorf("failed allowing VPN connection through firewall: %w", err)
+		return nil, "", fmt.Errorf("allowing VPN connection through firewall: %w", err)
 	}
 
 	runner = openvpn.NewRunner(settings.OpenVPN, starter, logger)

internal/vpn/portforward.go

@@ -16,7 +16,7 @@ func (l *Loop) startPortForwarding(ctx context.Context, data tunnelUpData) (err
 	// only used for PIA for now
 	gateway, err := l.routing.VPNLocalGatewayIP(data.vpnIntf)
 	if err != nil {
-		return fmt.Errorf("cannot obtain VPN local gateway IP for interface %s: %w", data.vpnIntf, err)
+		return fmt.Errorf("obtaining VPN local gateway IP for interface %s: %w", data.vpnIntf, err)
 	}
 	l.logger.Info("VPN gateway IP address: " + gateway.String())
 
@@ -28,7 +28,7 @@ func (l *Loop) startPortForwarding(ctx context.Context, data tunnelUpData) (err
 	}
 	_, err = l.portForward.Start(ctx, pfData)
 	if err != nil {
-		return fmt.Errorf("cannot start port forwarding: %w", err)
+		return fmt.Errorf("starting port forwarding: %w", err)
 	}
 
 	return nil

internal/vpn/wireguard.go

@@ -18,7 +18,7 @@ func setupWireguard(ctx context.Context, netlinker NetLinker,
 	wireguarder *wireguard.Wireguard, serverName string, err error) {
 	connection, err := providerConf.GetConnection(settings.Provider.ServerSelection, ipv6Supported)
 	if err != nil {
-		return nil, "", fmt.Errorf("failed finding a VPN server: %w", err)
+		return nil, "", fmt.Errorf("finding a VPN server: %w", err)
 	}
 
 	wireguardSettings := utils.BuildWireguardSettings(connection, settings.Wireguard, ipv6Supported)
@@ -29,12 +29,12 @@ func setupWireguard(ctx context.Context, netlinker NetLinker,
 
 	wireguarder, err = wireguard.New(wireguardSettings, netlinker, logger)
 	if err != nil {
-		return nil, "", fmt.Errorf("failed creating Wireguard: %w", err)
+		return nil, "", fmt.Errorf("creating Wireguard: %w", err)
 	}
 
 	err = fw.SetVPNConnection(ctx, connection, settings.Wireguard.Interface)
 	if err != nil {
-		return nil, "", fmt.Errorf("failed setting firewall: %w", err)
+		return nil, "", fmt.Errorf("setting firewall: %w", err)
 	}
 
 	return wireguarder, connection.ServerName, nil